JP3559473B2 - Observation optical equipment - Google Patents

Description

[0001]
【Technical field】
The present invention relates to a tiltable observation optical apparatus that can focus an eyepiece optical system on a plane that is not perpendicular to an optical axis of an objective optical system.
[0002]
[Prior art and its problems]
With conventional observation optical instruments such as binoculars and telescopes, focus can be achieved only on a plane perpendicular to the optical axis of the objective optical system. Some objects, etc.) were out of focus. In particular, focusing on only a part of a very close-up surface, such as a close-up distance, required re-focusing many times to observe the entire surface. For example, when looking at the blackboard in the university lecture room from the edge of the front row, or when monitoring the walls of a large room from the four corners of the room, it may be troublesome because the focus range in the field of view is narrow. there were.
[0003]
[Object of the invention]
An object of the present invention is to provide an observation optical apparatus that can focus on an entire surface that is not perpendicular to the optical axis of an objective optical system based on the above problem awareness.
[0004]
Summary of the Invention
The observation optical apparatus according to the present invention includes an observation optical system for enlarging and observing an object image formed by an objective optical system with an eyepiece optical system, and disposing a diffusion plate at an image plane position of the objective optical system. The eyepiece optical system and the eyepiece optical system are integrated, and the rotation can be adjusted with respect to the objective optical system side around the point where the optical axis of the objective optical system intersects with the diffusion plate.
[0005]
It is preferable that the center of the diffuser plate coincides with the optical axes of the objective optical system and the eyepiece optical system. In order to focus on different object distances, the position of the eyepiece optical system and the diffuser can be adjusted in the optical axis direction of the objective optical system.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The binoculars according to the present embodiment include a pair of symmetrical objective optical system holders 12 pivotally mounted on an interpupillary distance adjustment axis 11, and an objective lens group (objective optical system) 13 in each objective optical system holder 12. And the erecting prism 14 is fixed. The optical axis 13X of the objective lens group 13 is bent by a Porro prism (erect prism) 14 composed of the two right-angle prisms 14a and 14b.
[0007]
At the rear of each objective optical system holder 12, a concave truncated conical connection plate 15 centered on the optical axis 13X is fixed, and the connection plate 15 has an eyepiece lens group (eyepiece optical system) 16 An eyepiece optical system holder 18 having a diffusion plate 17 is supported.
[0008]
Each connection plate 15 is positioned in the horizontal direction (the plane direction connecting the optical axes of the left and right objective lens groups 13) and the vertical direction with the optical axis 16X of the eyepiece lens group 16 interposed therebetween (only the horizontal direction in the figure). Are shown), and a driven forward / backward pin (needle) 21 and a driving forward / backward pin (needle) 22 are provided. The needle portions 21a, 22a at the distal ends of the driven advance / retreat pin 21 and the drive advance / retreat pin 22 abut on the spherical surface of the front end (the end on the side of the objective optical system holder 12) of the eyepiece optical system holder 18, respectively. The driven advance / retreat pin 21 is urged by a compression spring 23 in a direction protruding toward the eyepiece optical system holder 18. The driven advance / retreat pin 22 has a pinion 24 on a rack 22 b (FIG. 4) formed parallel to the axis thereof. Are engaged. The pinion 24 is rotationally driven by a forward / reverse drive motor 25 and a speed reduction mechanism 26.
[0009]
The eyepiece optical system holder 18 is urged to move toward the connection plate 15 by urging means (not shown) to prevent the eyepiece optical system holder 18 from falling off from the connection plate 15. Accordingly, the compression spring 23 of the driven advance / retreat pin 21 is constantly compressed. When the forward / backward position of the driving forward / backward pin 22 in the axial direction is changed by the forward / reverse drive motor 25 and the speed reduction mechanism 26, the driven forward / backward pin 21 moves backward when the driving forward / backward pin 22 advances, and advances when moving backward. As a result, the eyepiece optical system holder 18 rotates with respect to the connection plate 15. The rotation center X is located on the optical axis 13X and on the surface of the diffusion plate 17 on the objective lens group 13 side.
[0010]
The left and right connection plates 15 are provided for the driven advance / retreat pin 21, the driving advance / retreat pin 22, the compression spring 23, the pinion 24, the forward / reverse drive motor 25, and the speed reduction mechanism 26, respectively. Set exists. In FIG. 4, only the forward / reverse drive motor 25 includes the forward / reverse drive motors 25H1 and 25H2 for the horizontal direction and the forward / reverse drive motors 25V1 and 25V2 for the vertical direction. These four forward / reverse drive motors 25 are synchronously controlled by a four-direction (all directions) operation button 27 and a control circuit 28.
[0011]
The eyepiece lens group 16 and the diffusion plate 17 are fixed to an eyepiece optical system holder 18, and the eyepiece optical system holder 18 and the connection plate 15 can be adjusted in the optical axis direction with respect to the objective optical system holder 12. . In other words, the surface of the diffusion plate 17 can be observed by making the surface of the diffuser plate 17 coincide with the image formation position of the object image by the objective lens group 13 which differs depending on the object distance. The movement in the optical axis direction, that is, the focus adjustment can be performed manually or electrically.
[0012]
When the four forward / reverse drive motors 25 are synchronously driven in the forward / reverse direction via the four-direction (all-directions) operation buttons 27 and the control circuit 28, the observation optical device having the above-described configuration moves the eyepiece optical system holder 18 to the rotation center X , The optical axis 16X of the eyepiece lens group 16 is displaced from the optical axis 13X of the objective lens group 13 held in the objective optical system holder 12 (the optical axis 16X and the optical axis 13X are An angle other than 180 ° can be formed at point X).
[0013]
FIG. 5 shows the forward and reverse rotation of the eyepiece group 16 about the rotation center X. The middle part of the figure shows the optical axis 16X of the eyepiece group 16 and the optical axis of the objective lens group 13. The state where 13X coincides, and the upper and lower stages respectively show the state in which the optical axis 16X is rotated around the rotation center X in the forward and reverse directions from the middle state. The middle state corresponds to the state shown in FIGS. 1 and 2. The diffusion plate 17 is orthogonal to the optical axis 13X of the objective lens group 13, and all objects on the surface orthogonal to the optical axis 13X are diffused. Focus on the plate 17. On the other hand, when the diffusion plate 17 is inclined with respect to the optical axis 13X of the objective lens group 13 as in the upper and lower stages (corresponding to FIGS. The object on the surface is focused on the diffusion plate 17, and this image can be observed with the eyepiece group 16. E. FIG. P indicates an eye point.
[0014]
FIG. 6 shows the principle. The conditions for imaging all of the object plane 30 on the diffusion plate 17 are such that the object plane 30, the extension surface of the diffusion plate 17, and the plane passing through the principal point of the objective lens group 13 and orthogonal to the optical axis 13X are straight. Intersect and is known as the Scheimpflug principle. That is, when the diffusing plate 17 and the eyepiece lens group 13 are tilted together around the point X so as to satisfy this condition, the surface of the object having a depth oblique to the optical axis 13X of the objective lens group 13 is obtained. You can focus on 30. Since the focus plane, that is, the diffusion plate 17 is enlarged and observed by the eyepiece lens group 16 having the optical axis 16X perpendicular to the diffusion plate 17, the depth is oblique to the optical axis 13X of the objective lens group 13. It is possible to clearly observe the surface 30 of the object having the image.
[0015]
Now, the object distance from the principal point of the objective lens group 13 to the object plane 30 is D0, the angle between the plane orthogonal to the optical axis 13X of the objective lens group 13 and the object plane 30 is θ, the principal point of the objective lens group 13 When the distance between the light source and the diffusion plate 17 (the rotation center X) is L, and the angle between the diffusion plate 17 and a plane orthogonal to the optical axis 13X is α,
D0 · tan (90 ° −θ) = L · tan (90 ° −α)
When the relationship is satisfied, all the inclined object planes 30 can be imaged on the diffusion plate 17.
[0016]
Specific examples of the object distance and the inclination will be described.
Example 1
D0 = 2m
When θ = 60 ゜ L = 100 mm,
α = 4.95 ゜ Example 2
D0 = 2m
When θ = 30 ゜ L = 100 mm,
α = 1.65 ゜ Example 3
D0 = 1m
When θ = 45 ° L = 100 mm,
α = 5.71 ゜
In this way, even when the distance to the object is 1 to 2 m and the angle between the optical axis 13X of the objective lens group 13 and the object plane 30 is 30 to 60 °, the diffusion plate 17 is moved together with the eyepiece lens group 13. By inclining from about 2 ° to about 6 °, a clear image of the entire object plane 30 can be observed.
[0018]
Note that the principle of Scheimpflug is used, for example, in a tilt photographing mechanism of a large camera. That is, the focus range can be controlled or the perspective can be controlled by tilting, but since the optical axis of the lens and the center of the film are generally displaced during photographing, a considerably large image circle is required for the photographing lens. The shift lens of a 35mm SLR camera is used to correct the upper stenosis of a building by moving the lens parallel to the film (only perspective control is possible). Therefore, the focusing area cannot be focused on the object side surface that is not perpendicular to the optical axis of the objective optical system. Also, the shift lens requires a large image circle, which leads to an increase in cost. The depth of field (range of focus) can be increased by stopping down the aperture even with a general shooting lens, but using a tilt can increase the depth of field without stopping down, which is extremely advantageous in terms of image brightness. It is. Further, in the observation optical system, since the eyepiece optical system is generally smaller than the objective optical system, it is more advantageous to tilt the eyepiece optical system than the objective optical system in terms of miniaturization and cost.
[0019]
Further, the center of the diffusion plate 17 is located on the optical axis 13X of the objective lens group 13, and the diffusion plate 17 and the eyepiece group 16 can be tilted with the rotation center X passing through the surface of the diffusion plate 17 as the rotation center. Thus, the tilt can be performed without concern for the size of the image circle of the objective lens group 13 (or the objective lens group 13 and the erecting prism 14) (without regard to the peripheral light amount). In particular, when the erecting prism 14 is provided between the objective lens group 13 and the diffusion plate 17, tilting can be performed without concern for vignetting caused by the erecting prism 14 or the like. In general, in the case of binoculars or the like, the size of the erecting system has no margin in the limit of a range through which a light beam passes when there is no tilt or the like. Therefore, if the objective lens group 13 and the eyepiece are tilted, vignetting may occur and the periphery of the field of view may be dark or invisible, but the diffusion plate 17 does not cause such a problem.
[0020]
In order to focus on an observation object at a different object distance, the eyepiece optical system holder 18 is moved forward and backward with respect to the objective optical system holder 12, and the eyepiece lens group 16 and the diffusing plate 17 with respect to the objective lens group 13 (erect prism 14). What is necessary is just to change a relative position.
[0021]
In the above embodiments, the present invention is applied to binoculars. However, the present invention can be applied to general observation optical devices having an objective optical system and an eyepiece optical system such as monoculars.
[0022]
Further, in the above embodiment, the eyepiece lens group 13 (the eyepiece optical system holder 18) is rotatable in all directions around the rotation center X, but as a simple form, it can be rotated only in the horizontal direction. It may be possible to move.
[0023]
【The invention's effect】
According to the present invention, it is possible to obtain an observation optical apparatus that can focus an eyepiece optical system on a surface that is not perpendicular to an optical axis of an objective optical system.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment in which an observation optical device according to the present invention is applied to binoculars.
FIG. 2 is an enlarged sectional view of an eyepiece optical system portion of the binoculars of FIG.
FIG. 3 is a cross-sectional view showing a state where an eyepiece optical system of the binoculars of FIG. 1 is tilted.
FIG. 4 is an enlarged sectional view of an eyepiece optical system of the binoculars of FIG. 3;
FIG. 5 is a development view of the binoculars of FIG. 1;
FIG. 6 is an optical diagram illustrating the principle of Scheimpflug.
[Explanation of symbols]
11 Eye width adjustment axis 12 Objective optical system holder 13 Objective lens group (Objective optical system)
14 Upright prism 15 Connection dish 16 Eyepiece lens group (eyepiece optical system)
17 Diffusion plate 18 Eyepiece optical system holder 21 Follower advance / retreat pin 22 Driving advance / retreat pin 23 Compression spring 24 Pinion 25 Forward / reverse drive motor 26 Reduction mechanism 27 Four-direction (all directions) operation button 28 Control circuit

Claims (3)

In an observation optical system in which an object image formed by an objective optical system is enlarged and observed by an eyepiece optical system,
Disposing a diffusion plate at the image plane position of the objective optical system,
The diffusing plate and the eyepiece optical system are integrated with each other, and the rotation can be adjusted with respect to the objective optical system around a point where the optical axis of the objective optical system and the diffusing plate intersect. Observation optics. 2. The observation optical apparatus according to claim 1, wherein the center of the diffusion plate coincides with the optical axes of the objective optical system and the eyepiece optical system. 3. The observation optical device according to claim 1, wherein the position of the eyepiece optical system and the diffusing plate is adjustable in the optical axis direction of the objective optical system.

Images